1. Field of the Invention
The present invention relates to a hair growth phase extender composition. More specifically, it relates to a hair growth phase extender composition which maintains or extends the growth phase in the hair cycle by promoting hair growth.
2. Description of the Related Art
In modern day society, called a high aging society, high stress society, the opportunities for the hair on the head to be exposed to the risk of loss have become increasingly prevalent due to various factors.
To deal with this, various attempts have been made to provide more superior "hair tonics".
The main effects which hair tonics have on the hair are (1) an effect of inducing hair formation (effect of promoting hair formation and effect of inducing growth phase), (2) an effect of thickening hair, (3) an effect of extending the growth phase of hair, (4) an effect of inhibiting 5.alpha.-reductase, (5) an effect of promoting blood circulation, (6) a sterilizing effect, (7) an anti-dandruff effect, (8) a moisturizing effect, (9) an anti-oxidation effect, and other effects.
However, despite the various attempts made in this way, conventional hair tonics have not necessarily sufficiently acted to prevent hair loss, promote hair formation, etc. This is believed to be because there are probably various reasons for hair loss and the mechanism of hair formation is extremely complicated. The "hair tonics" provided up to now have been developed focusing on the relatively general concept of hair loss, in other words, the phenomenon of "hair loss". Not that many have been developed delving into the mechanism of the same.
The major reason is undeniably due in part to the fact that no sufficient method of evaluating hair growth drugs has been proposed enabling simple evaluating of the effect of hair formation focusing on this mechanism. In particular, it is difficult to establish a method of evaluating hair growth drugs which evaluates the (3) effect of extension of the hair growth phase. As a result, the hair tonics provided up to now have mostly focused on the above (1) effect of inducement of hair formation which promotes hair by inducing hair in the growth phase of the hair cycle and the (4) effect of blocking 5.alpha.-reductase.